Most of the items listed in every section work well in many search engines not just Google.

I would say a sitemap is important if you have a bigger site.

I would also say in the "factors that may count against you" to watch out for building up reciprocal inbound links to quickly. The one-ways do not matter as much, because there is no way to control who links to you (if your site is popular you may get 1000's of one-way links overnight). It is my belief that the only links NOT to build to quickly are reciprocal ones that Google may view as a "non-natural" link.

Another great addition to the "links" section on your list would be a submission to DMOZ directory (http://www.dmoz.org). Dmoz results are used in the Google Directory and show up near the top of search engine results pages all over targeted keyword terms. Dmoz allows webmasters to use their results as suplimental search results in website directories, or as a full site directory or even just one or two categories. Since they allow this that means depending on what category you are in, you could have other people adding it to their own site directory. Whats good about that? Well if 1000 people have your Dmoz category content on their site and your link is on the page you could potentially have 1000 links to your site (this is only from sites and urls that are indexed in google. Msn and yahoo index a lot more of these pages than google does, simply because google does not want the same content in thier index.

I will add more later if any comes to mind, but I really like what you have started so far on this Google Ranking Factors List.